Electric Hand Held Tool Device

ABSTRACT

The invention relates to an electrical hand tool device, particularly a drill, screwdriver, hammer drill, or percussion drill, with at least an optional rotating drive for a tool mountable in a tool receptor, with a motor housing ( 10 ) and a transmission housing that is separate from the motor housing ( 10 ) but connected with it, whereby the motor housing ( 10 ) is formed of two half-shells ( 12, 14 ) that essentially lie within a plane extending along the longitudinal axis of the electrical hand tool device and dividing the electrical hand tool device essentially into two symmetrical halves ( 12, 14 ) with their side edges matching each other, whereby a handgrip ( 30 ) is provided on the motor housing, and whereby the two half-shells ( 12, 14 ) are connected with each other by means of a clip ( 18 ) extending longitudinally holding them clamped together.

The invention relates to an electrical hand tool device, particularly a drill, screwdriver, hammer drill, or percussion drill, with at least an optional rotating drive for a tool mountable in a tool receptor, with a motor housing and a transmission housing that is separate from the motor housing but connected with it, whereby the motor housing is formed of two half-shells that essentially lie within a plane extending along the longitudinal axis of the electrical hand tool device and dividing the electrical hand tool device essentially into two symmetrical halves with their side edges matching each other, and whereby a handgrip is provided on the motor housing. Such a design for electrical hand tool devices has been known for many years whereby the plane within which the half-shells rest against each other essentially divides the machine into a left half and a right half when in the normal use position.

For this, the two side edges of the two half-shells rest against each other. On the end facing the tool receptor, the transmission housing is connected to the motor housing and is connected with it. It is usual for this to connect the two housings using threaded fasteners.

The two housing shells of the motor housing are also usually connected with each other using threaded fasteners.

It is the task of the invention to provide an electrical hand tool device with an alternative method of securing the half-shells of the motor housing.

This task is solved by a conventional electrical hand tool device whereby the two half-shells are held together by means of a clip extending longitudinally. For this, the clip overlaps the adjacent side edges of the half-shells and connects them specifically by means of clamping, i.e., a non-positive method. In general other types of connection are conceivable, such as an engaging method. A non-positive connection method is preferred, however, to keep the play between the housing halves to a minimum. For this, securing or engaging media are provided that interact with corresponding securing or engaging media on the side edges of the half-shells. Ribs or clinches may in particular be provided in the area of the side edges of the half-shells that are in clamped contact with ribs or clinches, or with the side walls, of the clip, and are preferably overlapped by the clip. A flat or arched, or particularly a bomb-shaped material that extends longitudinally is used as a clip whose length is considerably greater than its width, whereby the height may vary along its length. The clip possesses a band-like shape. Also, the half-shells of the housing and of the handgrip may also be connected together using threaded connectors.

Moreover, the motor housing may also be attached to the transmission housing by means of the clip. For this, the clip includes connector elements between the two housings, and allows mounting on the transmission housing such that the half-shells of the motor housing rests firmly against matching edge of the transmission housing, providing contact between the two housing parts with no play. For this, the clip mounted on the transmission housing by means of a threaded connector may be provided. This offers the advantage that the attachment need not be in one or both half-shells which are generally made of plastic components which are more difficult to produce because of injection molding, but rather in a technologically simple clip that is stronger because of its clamping function and that is preferably made of metal.

It may thus be advantageous for the provided clip to completely surround the motor housing in the area of the opposing side edges of the half-shells. In this manner, a secure clamping is achieved along the entire length of the opposing side edges while intrusion of dust etc. into the motor housing is prevented by the clip surrounding both side edges. Moreover, this configuration allows achievement of a particularly pleasant appearance. Further, another seal may be provided in the area of the overlap of the clip over the side edges so that the degree of seal may be increased. The clip may thus be pressed longitudinally over the end of the motor housing facing away from the transmission housing.

Further, it may be provided that the handgrip is also formed of two shells, and particularly that each shell of the handgrip is connected with a half-shell of the motor housing as one piece. Such a design offers the advantage that the half-shells may be produced of plastic together with the half-shells of the handgrip using injection molding. In an electrical hand tool device, the number of parts necessary for the housing may thus be reduced, resulting in reduced installation costs.

It may further be provided that the clip connects the handgrip with the motor housing unless a one-piece design is used.

In both cases, it may be provided that the shells of the handgrip are connected with each other by means of the clip. For this, the clip surrounds the side edges of the shells of the grip on at least one side of the grip and presses these edges together advantageously. For this, connection elements may again be provided on the shells of the grip. Alternatively, an engaging connection is possible.

It may further be provided that the clip that covers the handgrip on one side has visual continuity along the direction toward the transmission housing by means of a grip protector that is formed as a separate component so that a visual arch results for which one part of the arc is formed by the clip on the handgrip, in which area a switch etc. may be provided, and the arc then extends toward the transmission housing such that the hand holding the handgrip is protected by this additional part of the arc. The arc may then extend as far as the end of the transmission housing that includes a tool. For this, the clip and the grip protector are of the same material or color.

It may also be particularly advantageous for the handgrip to be positioned at the center of gravity of the electrical hand tool device. Such a configuration is already known from DE 10 204 003 027 B3 which describes an electrical hand tool device in which the handgrip in the use position may be mounted on the upper side of the housing, and whereby the handgrip is so inclined that its free end points toward the tool receptor. Placing the handgrip at the center of gravity of the electrical hand tool device offers the advantage that the machine, for example, may rest against the forearm of the user with the part of the motor housing facing away from the tool receptor, and thus may serve as lower-arm support. Moreover, such a design offers the advantage that the configuration of the handgrip at the center of gravity offers particularly good balance of the tool, and thus tilting of the tool during operation may largely be prevented. The holding and support effort by the user is thus reduced.

Particularly if the handgrip is inclined toward the tool to be received, there is the additional advantage of ergonomic gripping of the machine particularly when the machine is operated with the handgrip pointing upward, whereby this position is to be designated as the operating position, in contrast to the pistol-grip style operating position with conventional electrical hand tool device of this type. Tilting the tool may thus be further prevented and force that would normally be required to stabilize the electrical hand tool device may now be applied to the work, whereby fatigue is clearly reduced.

Additionally, positioning of the handgrip at the center of gravity with the grip pointing upward allows easier grasping and raising the machine, especially with one hand, whereby the wrist bears less load since no rotational motion need be performed.

According to an advantageous embodiment of the invention, it may be provided that the handgrip is mounted at such an angle to the longitudinal axis of the electrical hand tool device that is particularly formed by the drive axis in extension of the tool receptor and the tool that an angle of between 5° and 30° exists between a longitudinal axis of the forearm of the user and the tool longitudinal axis.

It may also be particularly advantageous for the extension of the longitudinal axis of the electrical hand tool device to coincide with the extension of the forearm of the user near the tool, particularly in the area of the free tip of the tool, i.e., the two force lines intersect advantageously near the tip of the tool, allowing achievement of a particularly favorable force input with simultaneous precise control.

It may also be provided that one or more resting surfaces on which to rest the electrical hand tool device are provided on the underside of the electrical hand tool device in operating position. This allows for an electrical hand tool device that had been set down to be picked up directly in the operating position without having to tilt the reposing electrical hand tool device that is resting on one of the two half-shells of the motor housing before operation may begin. This further protects the user's wrist. In particular, one-handed pick-up may be performed, and the other hand is not required to position [the electrical hand tool device] in the operating position for a drilling operation, for example. For this, it may be particularly provided that a flat area is located in the area of the clip on which the electrical hand tool device may be stood upright.

It may also be provided that a second supplemental handgrip be mounted for two-handed operation. This second handgrip may be positioned in the conventional manner behind the tool receptor with respect to the tool and, for example, by means of a strap that is provided at the appropriate position behind the tool receptor of a tool, be positioned on, and affixed to, the electrical hand tool device.

It may moreover be provided that the transmission housing and/or the clip are of aluminum. For this, an aluminum injection-molded housing and a clip of the same material are involved. A proper metallic transmission housing allows for longer machine service life. The machine is first stronger, and second, better conducts arising heat away from the transmission housing.

Further, provision of a clip of die-cast aluminum increases the solidity of the machine, and particularly improves its appearance.

The half-shells of the motor housing and/or the shells of the grip may be of plastic. For this, it may be provided that actuation elements such as the switch are located in the area of the plastic housing of either the half-shells or of the grip. To improve appearance and machine solidity, it may further be provided that carbon-fiber appliqués are mounted that may cover in particular the visible areas of the half-shells of the motor housing.

It may overall be provided that the clip is implemented as a flat clip rising only barely above the half-shells for almost its entire extent. Areas may also be provided, however, in which the clip rises farther above the half-shells for the purpose of improving device design.

It may particularly be provided that the plastic housing or the cover of carbon fiber, which may particularly be provided in the area of the transmission housing, contrasts in color in a pleasing fashion from the die-cast aluminum of the transmission housing and of the clip.

Further advantages and properties of the invention derive from the Dependent Claims. In the following, the invention will be described in greater detail using Figures, which show:

FIG. 1 motor housing of an electrical hand tool device;

FIG. 2 cross-section view along projection A-A; and

FIG. 3 cross-section view along projection B-B in FIG. 1

FIG. 1 shows a motor housing that is provided with reference index 10. The motor housing 10 here is formed of two half-shells 12 and 14 that consist of a plastic material and are produced using injection molding. The two half-shells 12 and 14 are connected together using a tongue-and-groove connection. In order to prevent unintentional separation of the two half-shells 12 and 14 from each other, a clip 18 is provided that provides a clamping of the two half-shells 12 and 14 against each other, whereby ribs 19 and 20 are provided on the half-shells 12 and 14 as clamping media that engage into recesses 21 and 22 of the clip 18, whereby the side walls of the recesses form matching clamping media and are so positioned that the two ribs are pressed against each other, providing a clamping effect of the half-shells 12 and 14 in the upper area of an electrical hand tool device. Two ribs are also provided on the lower area of the motor housing, designated with indices 23 and 24, which are not separated from each other, but rather in whose vicinity the tongue-and-groove slot is provided. Here also, an opposing pressing of both ribs 23 and 24 is performed by the clamping media on the clip 18.

The clip 18 is hereby is formed to fit completely around the motor housing in the vicinity of the opposing side edges of the two half-shells 12 and 14,

Further, a handgrip 30 is provided by means of which the electrical hand tool device may be held by the user.

The handgrip 30 for this is positioned on the conventional operating and pick-up position of the machine on its upper side near the motor housing where it connects to the transmission housing (not shown). This position corresponds essentially to the center of gravity of the electrical hand tool device. Thus, balanced operation may be performed with minimal effort and fatigue. The handgrip 30 is slightly inclined toward the tools receptor (not shown) in order to improve ergonomics. The clip 18 thus extends over one side of the handgrip 30, and the two shells 12 and 14 of the handgrip 30 (designated with 31 and 32) are clamped to each other by means of the tongue and groove using side elements 34 and 35 that form the clamping elements of the clip [18] in this area. Switches 36 to operate the electrical hand tool device are provided on the side of the handgrip 30 facing away from the clip 18.

For this, the clip 18 is essentially a flat surrounding band, a widened section 37 is provided only in at the rear edge of the motor housing where a surface can be enlarged for standing the electrical hand tool device and to bear the power cable. The clip 18 possessing a flattened standing surface 40 on its lower side may be provided. Moreover, the clip may be bomb-shaped in order to provide a pleasing appearance. The electrical hand tool device may be stood upright on the standing surface 40 so that it is not necessary to lay the electrical hand tool device on the side surfaces of the half-shells 12 and 14. A first pivoting motion and gripping with the other hand in order to bring the machine into operating position is not necessary.

It may moreover be provided that ventilation apertures 42 are provided in the motor housing.

According to a particularly advantageous embodiment example, the visible areas of the motor housing are covered by carbon-fiber appliqués 43 and 44 that provide the machine or the electrical hand tool device with a high-value visual image.

The connection with the transmission housing may be accomplished here in the conventional manner, whereby the connection elements are provided in the clip 18 as well as in the transmission housing.

It may be further be provided that the end of the clip 18 on the handgrip 30 interacts with the matching additional clip element (not shown), which serves as a grip protector, and whose other end is attached to the transmission housing. 

1. Electrical hand tool device, particularly a drill, screwdriver, hammer drill, or percussion drill, with at least an optional rotating drive for a tool mountable in a tool receptor, with a motor housing (10) and a transmission housing that is separate from the motor housing (10) but connected with it, whereby the motor housing (10) is formed of two half-shells (12, 14) that essentially lie within a plane extending along the longitudinal axis of the electrical hand tool device and dividing the electrical hand tool device essentially into two symmetrical halves (12, 14) with their side edges matching each other, whereby a handgrip (30) is provided on the motor housing, characterized in that the two half-shells (12, 14) are connected with each other by means of a clip (18) extending longitudinally holding them clamped together.
 2. Electrical hand tool device as in claim 1, characterized in that the clip (18) completely surrounds the motor housing (10) in the area of the opposing side edges of the half-shells (12, 14).
 3. Electrical hand tool device as in claim 1, characterized in that the handgrip (30) is formed of two shells, and particularly that each shell (31, 32) of the handgrip (30) is formed of one piece with a half-shell (12, 14) of the motor housing (1), and the clip (18) connects the shells (31, 32) of the handgrip (30) together.
 4. Electrical hand tool device as in claim 1, characterized in that the clip (18) connects the handgrip (30) to the motor housing (10).
 5. Electrical hand tool device as in claim 1, characterized in that the handgrip (30) is positioned at the center of gravity of the electrical hand tool device.
 6. Electrical hand tool device as in claim 1, characterized in that the handgrip (30) is attached to the motor housing (10) near its connection with the transmission housing.
 7. Electrical hand tool device as in claim 1, characterized in that the handgrip (30) is inclined toward the tool to be inserted.
 8. Electrical hand tool device as in claim 1, characterized in that the handgrip (30) is mounted on the upper side of the electrical hand tool in its operating position.
 9. Electrical hand tool device as in claim 1, characterized in that an additional supplemental handgrip may be mounted for two-hand operation.
 10. Electrical hand tool device as in claim 1, characterized in that the transmission housing and/or the clip (18) are made of aluminum.
 11. Electrical hand tool device as in claim 1, characterized in that the half-shells (12, 14) of the motor housing (10) and/or the shells (31, 32) of the grip (30) are made of plastic.
 12. Electrical hand tool device as in claim 2, characterized in that the handgrip (30) is formed of two shells, and particularly that each shell (31, 32) of the handgrip (30) is formed of one piece with a half-shell (12, 14) of the motor housing (1), and the clip (18) connects the shells (31, 32) of the handgrip (30) together.
 13. Electrical hand tool device as in claim 2, characterized in that the clip (18) connects the handgrip (30) to the motor housing (10).
 14. Electrical hand tool device as in claim 3, characterized in that the clip (18) connects the handgrip (30) to the motor housing (10). 